US EPA Initially 20011231 (see Maintenance_and_Update_Frequency) vector digital data Water Quality Standards 1 Washington, DC US EPA http://www.epa.gov/waters/data/downloads.html State (also includes DC, tribes, and territories; i.e., "jurisdictions") Water Quality Standards' Designated Uses for river segments, lakes, and estuaries. The Water Quality Standards' Designated Uses are able to be linked to tables of water quality criteria which are located in EPA's Water Quality Standards Database. Water Quality Standards coded onto route.rch (Transport and Coastline Reach) feature of the National Hydrography Dataset (NHD) to create NHD Linear and Point Events. Point events are attached to a reach in NHD for many reasons: to represent an estuary; represent a drinking water intake point; or to represent a designated use when there is no reach in NHD to represent that reach. Water Quality Standards coded onto the National Hydrography Dataset (NHD) Waterbody Reaches (region.rch) to create Waterbody Shapefiles. In addition to NHD reach indexed data there may also be custom shapefiles (point, line, or polygon) that are not associated with NHD and are in an EPA standard format that is compatible with EPA's Reach Address Database. These custom shapefiles are used to represent Water Quality Standards that are not represented well in NHD. To be used to identify the spatial extent of waters listed under State Water Quality Standards. These waters can be linked to EPA's Water Quality Standards Database for query and display. Procedures Used: From time to time beginning with initial publication, selected State Water Quality Agencies supply EPA's Office of Water with lists of waters with Designated Uses under State Water Quality Standards. These lists contain text which identify the locations of individual waters on their list. Many states also submit GIS coverages and or maps that outlined the spatial extent of their listed waters. These base materials are used by EPA to code the spatial extent onto route.rch (Transport and Coastline Reach) feature of NHD to create NHD Linear and Point Events. These base materials are used by EPA to code the spatial extent onto NHD Waterbody Reaches (region.rch) to create Waterbody Shapefiles. Using the EPA's NHD-Reach Indexing Tool (NHD-RIT), event tables/shapefiles are created and the reaches are identified with the Designated Uses supplied by the states. These event tables/shapefiles are then sent to each state for review and comment. The format of the reviewed data are state dependent. Formats consist of hardcopy maps, shapefiles or coverages with events. Revisions: Initial indexing is done and maps sent back to the state for review. In many cases, modifications are noted by the State and then corrections are made by RTI. These corrected event tables/shapefiles are then sent to each state for re-review and comment, or if correct, approval for display on the internet. NHD Vintage: NHD (Flow-validated, Re-leveled) -- Current as of June, 2002 (compatible with EPA Reach Address Database Version 2.0) 2001 (varies by and can vary within jurisdiction - from prior process date to most recent process date ). See Maintenance_and_Update_Frequency see Maintenance_and_Update_Frequency In work Publication to internet version of WQSDB every 6 months (April and October). Continous processing of updates of selected jurisdictions and partial jurisdiction (staged update) information. -180 -60 80 0 None designated uses reach indexing Metadata Service Theme Categories environment inlandWaters None US National Password protected until review is complete. The reach indexing review is designed for state review of DRAFT Water Quality Standards (WQS) spatial data. Research Triangle Institute (RTI), under contract with EPA, georeferences (or indexes) states' Water Quality Standards to the National Hydrography Dataset (NHD). EPA requires each state to review and approve the indexing work for display on the internet version of the WQSDB. Reviewers are asked to assess the accuracy of WQS reach indexing (georeferencing) efforts. More specifically, reviewers are asked to evaluate whether designated uses are assigned to the appropriate reaches and to assess the accuracy of the locational information. When using this data in a spatial query, errors in determining the overlap can occur. The errors can be grouped as follows: (1) False Positives occur when the locational information is either incorrect or not of sufficient quality to determine its exact location. (2) False Negatives occur when locational information is missing or not available. (3) In addition to the entity locational information, errors, although few, may also exist in the spatial network of rivers, streams, and other waterbodies that comprise the National Hydrography Dataset (NHD) jointly maintained by USGS and USEPA. Errors in the NHD may contribute both to false positive and false negative readings. Bill Kramer US EPA Headquarters mailing address

1200 Pennsylvania Avenue, NW Room 5233T, Mail Code 4305T EPA West

Washington DC 20460 202-566-0385 kramer.bill@epa.gov None Unclassified None ArcView 3.2 (used in conjunction with the Reach Indexing Tool (RIT) and the National Hydrography Dataset (NHD) - NHD (Flow-validated, Re-leveled) -- Current as of June, 2002 (compatible with EPA Reach Address Database Version 2.0), and/or EPA's Web-Based Reach Indexing Tool (WebRIT). Chain-node topology present State review underway. Statements of horizontal positional accuracy are based on accuracy statements made for USGS topographic quadrangle maps. These maps were compiled to meet National Map Accuracy Standards. For horizontal accuracy, this standard is met if at least 90 percent of points tested are within 0.02 inch (at map scale) of their true positions. Additional offsets to positions may have been introduced where there are many features to improve the legibility of map symbols. In addition, the digitizing of maps is estimated to contain a horizontal positional error of less than or equal to 0.003-inch standard error (at map scale) in the two component directions relative to the source maps. Visual comparison between the map graphic (including digital scans of the graphic) and plots or digital displays of points, lines, and areas is used to assess the positional accuracy of digital data. Linear features of the same type along the adjoining edges of data sets are aligned if they are within a 0.02-inch tolerance (at map scale). To align the features, the midpoint between the end of the corresponding features is computed, and the ends of features are moved to this point. Features outside the tolerance are not moved; instead, a feature of the type connector was added to join the features. For more information, see the National Hydrography Dataset Concepts and Contents document (February 2000) available at <http://nhd.usgs.gov/chapter1/index.html>. Statements of vertical positional accuracy for elevation of water surfaces are based on accuracy statements made for USGS topographic quadrangle maps. These maps were compiled to meet National Map Accuracy Standards. For vertical accuracy, this standard is met if at least 90 percent of well-defined points tested are within one-half contour interval of the correct value. Elevations of water surface printed on the published map meet this standard; the contour intervals of the maps vary. These elevations were transcribed into the digital data; the accuracy of this transcription was checked by visual comparison between the data and the map. For more information, see the National Hydrography Dataset Concepts and Contents document (February 2000) available at <http://nhd.usgs.gov/chapter1/index.html>. Selected states send RTI a marked up map or existing GIS coverage denoting the location and extent of each waterbody. Using the EPA's NHD Reach Indexing Tool, shapefiles/event tables are created by conflating the each State's data to NHD. Event identifiers are populated with State-provided designated use waterbody codes. Initially 20011231 (see Maintenance_and_Update_Frequency) Vector 1 1 Decimal degrees North American Datum of 1983 Geodetic Reference System 80 6378137 meters 298.257222101 Point and linear event themes, NHD waterbody shapefiles, and Custom Shapes (point, line, and polygon shapefiles that are not associated with NHD). Each point event theme applies to a point along a section of the National Hydrography Dataset (NHD), which is a comprehensive set of digital spatial data that contains information about surface water features such as lakes, ponds, streams, rivers, springs and wells. Line event themes apply to linear positions along sections of the NHD. Each waterbody theme applies to whole or portions of NHD waterbody reaches. All other point, line, and polygon shapefiles represent geometries that do not fall on the NHD network of streams/coastline and lakes/ponds. EPA's Web-Based Reach Indexing Tool (WebRIT) and EPA's National Hydrography Dataset Reach Indexing Tool (NHD-RIT). FID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Coordinates defining the features. EVENT_ID Unique ID for an event created based on date and time when the event was created, and a sequential number to provide uniqueness for events created at the same time. System created number (WebRIT or NHD-RIT) 2000010100000100001 9999123124000099999 P_MEAS Specifies the location of the point along a route. This field is only used for point event themes. EPA's WebRIT or NHD-RIT 0 200 EOFFSET Offset distance of event from associated NHD route reach location. This field is only used for point and linear event themes. User input 0 999999 DUU_ID Unique identifier of the digital update unit in the NHD database. This field is only used for point and linear events and NHD waterbody shapefiles. NHD 0000000001 9999999999 RCH_CODE Numeric code that uniquely identifies a reach in NHD, consisting of two parts: the first eight digits are the hydrologic unit code of the cataloging unit in which the reach is located; the last six digits are a sequentially, arbitrarily-assigned number. This field is only used for point and linear events and NHD waterbody shapefiles. NHD NHD Reach codes USGS NHD RCH_DATE Date that the reach code (Rch_code) was assigned, displayed as YYYYMMDD. This field is only used for point and linear events and NHD waterbody shapefiles. NHD 19970101 99991231 ATTR_PRG Indicates the attribute type or program being indexed. WebRIT or NHD-RIT Alphanumeric ASCII ATTR_VAL Value associated with the attribute program in the field Attr_prg. User Input Alphanumeric ASCII ENTITY_ID Identifier used to aggregate reaches into homogenous units. It is also used to link the event table to external data sources. Water Quality Standards Database Alphanumeric ASCII STATE State abbreviation according to the FIPS standard. The state used in this field is the geographic area (state) that the event is located in. User input Federal Information Processing Standard Two digit FIPS state code (character). META_ID Link to the metadata table System created number (WebRIT or NHD-RIT) Alphanumeric ASCII F_MEAS Specifies the start point of the event along a route. This field is only used for linear events. EPA's WebRIT or NHD-RIT 0 200 T_MEAS Specifies to end point of the event along a route. This field is only used for linear events. EPA's WebRIT or NHD-RIT 0 200 METERS Length along the reach (in meters). This field is only used for linear events. EPA's WebRIT or EPA's NHD-RIT 0 40,000,000 SQ_KM Area of the waterbody shape (in square kilometers). This field is only used for NHD waterbody shapefiles. EPA's WebRIT or EPA's NHD-RIT 0 40,000,000 The WebRIT online help and tutorial can be found at <http://www.epa.gov/waters/webrit/training.htm>. The NHD Reach Indexing Tool Users's Guide - October 2002 can be found at <http://www.epa.gov/waters/georef/UserGuide.pdf> Bill Kramer US EPA Headquarters mailing address

1200 Pennsylvania Avenue, NW Room 5233T, Mail Code 4305T EPA West

Washington DC 20460 202-566-0385 kramer.bill@epa.gov Downloadable Data 20040608 Bill Kramer US EPA Headquarters mailing address

1200 Pennsylvania Avenue, NW Room 5233T, Mail Code 4305T EPA West

Washington DC 20460 202-566-0385 kramer.bill@epa.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 local time http://www.esri.com/metadata/esriprof80.html ESRI Metadata Profile 200411021259000020041102